The present invention relates to cassette type tape recorders and more particularly to a cassette type tape recorder capable of surely releasing the locked state of a record button for putting the tape recorder in a record mode.
In general, a cassette type tape recorder adapted for dictation-recording using a small-size tape cassette has been designed so that a single manually operated control knob is used for putting the tape recorder in any of the play, stop, and rewind modes, and a manually operated record button is additionally provided for changing between recording and playing. For instance, for recording, the record button is pushed to be locked in the record mode position. The control knob is then switched between a play position and a stop position thereby causing the tape to travel and to stop respectively. According to this manual operation, dictation sound can be recorded as desired.
When the recorded sound is to be reviewed, the operator turns the control knob to its rewind position to put the cassette type tape recorder in the rewind mode and lets a desired amount of tape travel in the reverse direction; then the same control knob is turned to the play position again, and the tape recorder assumes a play mode state. Here, if the record button is kept depressed, the tape recorder is put in the record mode whereupon the control knob is set at the above play position, with the result that pre-recorded sound is erased unavoidably.
Accordingly, for eliminating the above described difficulty, the cassette type tape recorder of this type has been adapted so that locked state of the record button is set free automatically in response to manual operation of the control knob to the rewind position. This means that, when the cassette type tape recorder is in the record mode, a series of operations of the control knob to the rewind position and then to the original play position is capable of positively changing the record state of the cassette type tape recorder to the play mode via the rewind mode.
On the other hand, to release the tape recorder from the record mode in a case such as that where the recording is to be stopped for a long period of time, or where the recording is completed, the record button is required to be set free. In the cassette type tape recorder of the above described construction, only for returning the record button, it is necessary to turn the control knob until it reaches the rewind position. Therefore, there arises a problem in that the tape is unavoidably rewound a little, when the control knob is operated as described above. Once the tape has been rewound, the subsequent recording operation results in the last part of the sound prerecorded is inevitably erased, and the erased sound is unable to be reproduced.
In addition, as a mechanism for rotating the supply reel shaft at high speeds in the rewind mode state, a gear train mechanism has been adopted for assuring positive operation. The conventional cassette type tape recorders have not been provided with any special mechanism for appropriately adjusting the time instant when the drive gear comes to mesh with the driven gear in a relationship corresponding to the time instant when the motor starts.
Accordingly, there is a possibility that the motor starts to drive before the drive gear comes to mesh fully with the driven gear, when the control knob is turned to the rewind position. Therefore, difficulties arise in that the gear train mechanism generates noise at the time when the tape starts to travel, and further that the tape does not travel stably due to insufficient power transmission by the gear train mechanism.